The present invention relates to powered cable pullers for routing cables and wiring through conduits.
Cable pullers are well-known devices for pulling power cables, data cables, or other wiring through both horizontal and vertical building conduits; the cables are usually pulled upwardly (referred to as an “up-pull”) or downwardly (referred to as a “down-pull”). Typical cable puller designs include a rope that connects to and pulls cables through the conduit and a conduit adapter that connects to the conduit to help support the device. In some designs, the conduit adapter is reconfigurable or interchangeable with other adapters to connect to conduits of various sizes. Typical puller designs also include a boom connected to the conduit adapter that guides the rope to a drive unit that rotates to pull the rope. The boom includes multiple sections that are connected by one or more pivotal joints. The pivotal joints permit the boom to be accurately repositioned such that the device is suitable for use with conduits that terminate at various heights.
Typical cable puller designs, while eliminating the need for contractors or other technicians to manually pull cables through building conduits, include several drawbacks. For example, some pullers are designed to have relatively high pulling capacities (e.g., 6000 lbs or more) to overcome large friction forces when a cable is pulled through a long conduit. High pulling capacity is typically provided by using a larger drive unit. In addition, the boom and other components are typically thick metal components to provide durability and resistance to deflection due to the high pulling forces. As a result, the large drive unit and boom cause the device to be very heavy (e.g., 75 lbs. or more) and difficult to reposition. A technician can be fatigued easily by lifting and carrying such a puller if many consecutive pulls are performed.
A number of designs have been created in an attempt to overcome the drawback of having to carry a cable puller between different locations. For instance, some cable puller designs include a base with wheels that support the drive unit and the boom. Such designs permit even larger drive units and booms to be used to further increase pulling capacity. The size of the base may prevent these pullers from accessing smaller areas in which the aforementioned designs fit easily. In addition, puller designs with wheels are typically difficult for a technician to push because the base is only inches off the ground.
All of the aforementioned puller designs are difficult to accurately reposition after the puller is moved to the general location of the conduit (i.e., difficult to accurately adjust the boom to connect the conduit adapter to the conduit). This problem occurs in part due to the weight of the cable puller as described above. In addition, the pivotal joints of the boom each include a pin that must be completely removed to reposition the boom sections. After the boom is accurately repositioned, the pin must be inserted into the joint while holding the puller in engagement with the conduit. This can be particularly difficult if a single technician must set up the power puller without assistance.
Further still, some of the aforementioned designs require a technician to partially disassemble the boom to switch between appropriate up-pull and down-pull configurations. For example, it may be necessary to separate the boom sections and reverse the orientation of several boom sections relative other sections. Such actions can be time consuming and can fatigue a technician.
Considering the limitations of the previous powered puller designs, a need exists for a design that is easily moved and reconfigured at a work site. A need also exists for such a cable puller to have a high pulling capacity.